15 Common Kumquat Tree Problems: How to Fix Them, Solutions, and Treatment

Kumquats are hardy plants, and it doesn’t take much time to grow them properly in the garden. The diseases of the Kumquat trees are caused by fungi and sometimes pests; the damage they cause can make the tree sick. The good news is that the Kumquat trees are extremely resistant or even protected from citrus canker, affecting other members of the Citrus family.

Common Kumquat Tree Problems
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Left unchecked, pests on your Kumquat trees can damage and destroy your precious plants. During regular daily inspections, keeping a close watch on your plants will help you find any pests before causing irreparable damage. Healthy Kumquat trees can come back if you catch the pest quickly.  

Common Kumquat tree problems

The Kumquat tree is not bearing fruit


Sometimes your Kumquat tree needs more time to produce fruit. Plants often need to reach a certain maturity level before they flower.

Solution – The Kumquat will start bearing fruit in 2 to 3 years if they are grafted or grown from seed for 15 years. Choose a grafted Kumquat tree over a seed-grown tree for the fastest results. This process also helps you can still get flowers on a small plant. 

Check fruit season

Kumquat trees do not produce ripe fruits until three months after flowering, usually in winter. Kumquat trees have a long period of dormancy in winter and do not start growing until the weather warms again. 

Solution – Most flowering plants bloom in spring, so you may be surprised when your Kumquat tree doesn’t follow it. Kumquat trees need six hours of full and direct sunlight to produce flowers, which occur in the summer months.

Water properly

Avoiding giving over or underwater to your Kumquat tree; can be difficult to balance. 

Solution – You should water young sprouts a couple of times a week, but you need not tend mature plants as often. Furthermore, Kumquat trees thrive in humid environments, so if your plant is indoors, try to mist leaves to prevent them from drying and curling. The plant grows in Clay soil, as a result, the roots will rot. The best way to water Kumquat is from deep water. Deep water is the process of providing more water in less frequent intervals. It trains the Kumquat tree to grow long roots and resist more drought. 

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Kumquat Fruit
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Provide balanced nutrients

The most important nutrients for Kumquat and mostly citrus trees are nitrogen, magnesium, phosphorus, and potassium. It is also essential to have a properly balanced pH to give good fruit to the Kumquat trees. 

Solution – You can also plant Kumquat trees in soil with a wide range of pH values. Most nutrients are less available to the tree at high or very low pH values. A balanced soil pH provides the right nutrients for growth and fruit support.


The Kumquat trees are pollinated themselves, so they do not need another citrus tree nearby to produce fruit. Cross-pollination increases the amount and size of pollinated flowers and fruits. 

Solution – You can increase cross-pollination by planting flowering plants or using toothbrushes. Pollinators carry pollen from male to female flowers. Without pollination, the tree will bloom but will not produce Kumquat. Sometimes the trees of outdoor Kumquat still do not get enough pollination. One way to increase the chances of fruit production is to plant flowers in your garden. This can help attract more pollinators around the Kumquat tree and increase the level of pollination.

Yellow leaves on Kumquat trees

Yellow leaves on Kumquat trees are usually caused by overwater. However, other factors such as nutrient deficiency, root rot, and aphids can also cause this problem. 


Kumquat trees can get overwater and prepare yellow leaves quite easily if planted in clay or collapsed potting soil. 

Solution – Once the soil is well-drained, you can continue adjusting the amount of water and frequency. You should water Kumquat trees when their soil is dry. Further, use 1 to 2 inches of compost and mulch to improve water retention and prevent evaporation.

Nutrient deficiency

Unbalanced nutrients can cause Kumquat trees to fall yellow and droop leaves. 

Solution – Kumquat trees are quite heavy feeders of nitrogen, so they need to feed fertilizer about once to twice a year or during their growing seasons. Alternatively, you can feed compost to the Kumquat trees. If you go with compost, apply 2 inches every 1 to 2 months during the growing season.

Root rot 

Root rot causes yellowing and dropping leaves on Kumquat trees. Generally, root rot is caused by poor drainage and high water. Root rot slowly kills the rest of the tree. 

Solution – Root rot can usually be cured by repotting a tree with fresh soil. Other treatments, such as fungicides, but the repot is most effective. Changing the soil will remove most of the fungus and dry the rest. 


The aphids are small pests that feed on leaves, causing the tree to die slowly. In this process, the leaves of the Kumquat tree will start to turn yellow and fall. The aphids will appear as small dots and come in different colors, such as yellow, white, and black.

Solution – You can get rid of the aphids by spraying them with water, neem oil, or leaving ladybugs. 

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Kumquat Plant
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Dying Kumquat Tree

Kumquat trees usually die from inappropriate water, nutrients, or climate. However, transplant shocks, pests, and diseases can also affect them. Once the stress source is reduced, you should recover the Kumquat tree.

Over or underwater

Over and underwater usually leads to the dying Kumquat tree, with less water causing the most. Very little water and the Kumquat tree will turn brown and fall. Too much water causes root rot and leaves to fall. When the Kumquat trees are given less water, their leaves are curled to preserve moisture. 

Solution – Only water when the soil is dry and provides 2 inches of compost and mulch.

Transplant Shock

If the Kumquat tree was planted or replanted recently and has started to die, it is likely due to a transplant shock. 

Solution – Apply 2 inches of compost and 4 inches of mulch over the soil. Pour water and add more soil as needed.

Nutrient deficiency

Too little or too many nutrients on the Kumquat trees cause yellow and brown leaves. With very few nutrients, Kumquat trees cannot support the needs of their leaves, which then start to cause discoloration and death. 

Solution – If using chemical fertilizers, provide balanced NPK (nitrogen, phosphorus, and potassium) to the Kumquat trees, or you can apply 2 inches of compost every 1 to 2 months. 

Climate stress

The too cold or hot climate and dry quickly create a problem for tropical-loving Kumquat trees. 

Solution– keeping close to the sunny window; these conditions help mimic the tropical environment that Kumquat trees prefer.

Pests and diseases

Aphids, mealybug, and leaf scabs can cause Kumquat trees to die. 

Solution – Most pests can be prevented from water, oil, or spray, while you can treat diseases treated with organic sprays or fungicides. You can prevent pests and diseases like nematodes from fellow plants like Marigolds.

Kumquat tree drooping its leaves 

Improper soil moisture

Kumquat trees fall off leaves when they get too much or too little soil moisture. 

Solution – Water is often applied very frequently in insufficient quantities. Use a can to test to determine how often you should water the tree. Fill a can with 2 inches of water, when the can’s water is completely evaporated, water the tree and refill the can.

Cold damage

Kumquat trees lose leaves and fruits after severe freezing, although the Kumquat is known to be hardy below -5°C. 

Solution – If the Kumquat is grown in a container, bring it inside the house or to a shelter. If planted in the garden, remove the mulch from around the tree, water the soil well, and cover the tree. 

Pest damage

The Kumquats are susceptible to many diseases or pests. Some of these leaves may cause falls, but trees often appear earlier, with more indicative symptoms that help identify and treat specific insects. The Kumquats grown in the pot can be affected by mealybugs. Kumquats may be affected by scab, algal leaf spot, greasy spot, anthracnose, fruit rot, stem and root, and gummosis. 

Solution – You should use suitable pesticides to control pest damage. 

Rapid changes in light

Rapid changes in light can force the leaves to drop if Kumquat grown in containers moved to protect against cool temperatures. 

Solution – Slowly reduce or increase light daily for two to four weeks.

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Kumquat Farming
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Root problems

If the Kumquat grown in the container becomes rootbound, the twigs will die back, and the leaves will fall because the root system’s capacity is not balanced with the needs of the canopy. 

Solution – Gently prune the top back or repot the Kumquat into fresh soil. 

Kumquat tree dropping its fruits 

Commonly, the causes of the Kumquat tree drop fruit include natural fruit drops, inconsistent water, lack of nutrients, change in weather, and pest or disease attack.

Natural Kumquat Fruit Drop

All fruit trees leave some of their fruits at different stages of development. This ensures that the tree can deal with ripening the amount of remaining fruit. If it produced a huge Kumquat harvest last season, a higher percentage of fruits is likely to fall this season. Many commercial fruit farmers force the percentage of fruit to fall to ensure equal production over the years. So, if a Kumquat fruit falls, it is normal and not a cause for concern.

Inconsistent water 

The most common reason for premature fruit fall from Kumquat fruit trees is the amount of water they get. Drought conditions with very little water will stress the Kumquat tree and drop its fruit in its struggle to survive. Overwater, especially in pots, can cause nutrients to be leached in the soil, the tree becomes hungry, and the fruit drops.

Solution – Kumquat is like slow deep water every 3 to 7 days in hot weather and every 7 to 14 days in cold weather. You should water small trees more often than large trees because their root system is not so fully ready.

Nutrient deficiency 

Phosphorus deficiency is a common problem and usually does not result in tree flowering but can also cause fruit drops. Phosphorus is extremely important for plants, and it is almost impossible to overdose because it is difficult to absorb. 

Solution – Giving your Kumquat tree a good dose of compost can help it absorb phosphorus already present in the soil. You can add bone meal which is high in phosphorus and natural quantities.

Low potassium can cause fruit deficiency. Potassium organic sources are crab waste, burnt cucumber skins, kelp, banana peels, wood ash, and greensand. Dig some of them in the soil around your tree before watering. A lack of nitrogen can cause fruit to fall during the growing period. You can use Alfalfa meal, animal manure, and compost.

Change in weather 

A drastic change in weather can cause the Kumquat tree to be put under stress and its fruit to fall. Heavy frosts will cause all fruits of a particular stage to fall. The older the Kumquat tree, the more resistant it will be to the frost. 

Solution – If your Kumquat tree is young, covering it in the coldest months is a good idea. Different types of frost protection cover are available.

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Kumquat Garden
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Disease and pests 

Often pest attacks, such as mites, can cause fruit to fall, but it is usually late in the growing season. Black citrus aphids attack the fruit when it is too small and causes it to fall. 

Solution –To keep your garden completely organic, you can introduce natural predators such as lacewings or ladybugs to care for your aphid’s infection. You can use organic insecticidal soap and horticultural neem oil to deal with black citrus aphids.  

Kumquat leaves curling

Kumquat trees usually get curled leaves due to dehydration. However, inappropriate nutrients, aphids, severe weather, and transplant shocks can cause curled leaves. 


Giving underwater is the most common reason the leaves of the Kumquat trees are curled. When they don’t have enough water, the leaves are turned to maintain moisture. If it lasts long enough, the leaves will dry and turn yellow or brown before falling.

Solution – The best way to water the Kumquat trees is only when the soil is dry. You can apply 2 inches of compost and mulch to improve water retention and reduce evaporation. Compost is a wonderful soil modification as it provides enough nutrients for Kumquat trees and increases soil wealth. When applying compost or mulch, spread them evenly under the canopy of the Kumquat tree. 

Nutrient deficiency

Having unbalanced nutrients can make Kumquat trees grow curled leaves. When the Kumquat tree does not have enough nutrients to move around, it will start to shed less important parts of the tree that it cannot support. 

Sometimes a deficiency of nutrients can cause problems like dropping yellow leaves and leaves. The second time, flowers and fruits can also fall.

Solution – Use fertilizer to help prevent the curled leaves on the Kumquat trees with nitrogen twice as much as phosphorus and potassium. Apply 1 to 2 times yearly or use compost every 1 to 2 months during the growing season.


The aphids feed the juice from the leaves and can cause the leaves to curl on Kumquat trees. 

Solution – You can get rid of the aphids by spraying them with water or neem oil or leaving ladybugs in your garden. Lady bugs will help as they are a natural predator of the aphids.

Other stressors

Kumquat trees can also obtain curled leaves from extreme weather, transplant shocks, and competition from other plants.

Solution – For best results, place your Kumquat trees in temperatures between -6 to 30°C. If the temperature exceeds this limit, the potted Kumquat trees can be brought indoors, while the planted Kumquat trees can be shaded with heat or protected from sheets of cardboard from the cold. If you are transplanting or repotting your Kumquat tree, ensure the tree is planted quickly enough and the root ball is not damaged. While planting, maintain the same distance from other plants and structures such as foundations, fences, and fire hydrants.

Kumquat tree not flowering 

Many problems can cause your Kumquat not to flower at all. If your soil is too lean or soggy, your Kumquats cannot produce flowers. Kumquat trees also need zinc a lot. Zinc deficiency in soil can lead to the blooming of the Kumquat. 

Solution – Make sure the tree is planted in full sun, has rich, well-drained soil, and is properly cut. Fertilize your Kumquat tree monthly with zinc with good quality, organic citrus fertilizer. You can also spray on leaves with a micronutrient combination of zinc, iron, and manganese in the late spring at the beginning of the growing season.


Kumquat trees are susceptible to mealybug attacks, leaf miners, citrus scales, and aphids. Keep the soil thoroughly drained, avoid excess moisture, and collect too much mulch around the tree. 

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Kumquat Yiekd
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You can treat with horticultural neem oil.


They look like small white fifty cotton dots; they can be treated with horticultural soap.

Citrus scales

These pests look like small brown pieces and can be treated with horticultural neem oil.

Leaf Miners

When the larvae come out, they chew through the new growth of the leaf. Several ways to treat citrus leaf miners naturally, including horticultural neem oil. 



Anthracnose is a common citrus disease. 

Solution – You can prevent the disease with horticultural oil by spraying the tree thrice a year. If it seems, most copper-based fungicides will clean it up. You may also face Alternaria leaf spots, which you should be handled like anthracnose.

Citrus blast

The citrus blast causes wilting of leaves and can cause the complete death of the plant. 

Solution – You can use copper-based fungicides to eliminate this problem.

Phytophthora root rot

Phytophthora root rot is another problem that may appear on Kumquat trees. It is usually a fungi-based root rot caused by overly-soggy soil conditions. 

Solution – Don’t overwater your trees; you shouldn’t face this problem.

Root rot

Kumquats suffer from root rot diseases in poorly drained soil and flood-prone areas. 

Solution – The purpose of preventing this by choose a plantation site with good drainage and no more water.


Caring for a Kumquat tree is not difficult for a beginner gardener; you need to understand the right conditions, how often water, soil, and what if your plant ends up with a disease or insect. Small in size but large in fruit production, once-established Kumquat trees will take care of themselves and reward you.

Adjust your water routine and monitor your tree. Trees are always happy to get food for phosphorus, potassium, and nitrogen, so giving some can only benefit them.  Finally, find the symptoms of the insects and try to eliminate them. You can get healthy and delicious Kumquat fruit in no time.


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